I’ve heard that students involved in elementary debate are frustrated with their inability to find research that supports grade-level retention. This makes sense, as virtually none exists. However, research also points to poor outcomes for social promotion. So…the topic is best framed as alternatives to social promotion.
NCREL provides a pretty straightforward analysis of this point (http://www.ncrel.org/sdrs/areas/issues/students/atrisk/at800.htm). We looked at research like this when developing our progress/promotion policy. (As you know, that policy lists a number of alternatives to retention.)
I have no idea if it’s too late for this to be helpful to teachers and students, but thought I’d pass it along.
Carl